Wpływ chlorków w odpadach skał karbońskich GZW na otaczające środowisko wodne

Abstract

Odpady skał karbońskich deponowane na zwałowiskach zawierają znaczne ilości łatwo rozpuszczalnych soli chlorkowych. Badania wykazały, że zasolenie chlorkowe skał jest ściśle powiązane z koncentracją jonu Cl- w nasycających je wodach podziemnych. Zależność ta umożliwia prognozowanie zasolenia odpadów górniczych. Sole chlorkowe zawarte w tych odpadach są ługowane przez wody opadowe i stanowią źródło skażeń wód powierzchniowych i podziemnych w rejonie zwałowisk. Badania modelowe wykazały, że dynamika ługowania chlorków zależy od stopnia zasolenia chlorkowego skały oraz intensywności przepływu wód ługujących. INFLUENCE OF CHLORIDES FROM CARBONIFEROUS COAL MINE SPOILS ON SURROUNDING WATER ENVIRONMENT IN THE UPPER SILESIAN COAL BASINCarboniferous coal mine spoils set aside in mining of coal in the Upper Silesian Coal Basin mainly include claystones. The share of sandstones, coally shales, and coals is subordinate. The spoils yield large amounts of easily soluble chlorides (Table 1). Studies on water extracts from Carboniferous rocks (coals, sandstones, and claystones) and underground waters from natural effluences in the studied area showed that salinity of the rocks is due to presence of waters with varying concentrations of ion Cl- in pores of these rocks (Fig. 1). The recorded relationship of concentrations of ion Cl- in pore solutions of the rocks and underground waters makes possible prognosis of salinity of the rocks on the basis of concentrations of ion Cl- in ground waters (Fig. 2). Percolating precipitation waters are leaching chlorides from Carboniferous coal mine spoils and carry them to water environment which leads to increase in pollution of ground and surface waters in area of tips (Figs. 5-7).Model (lysimetric) studies showed that dynamics of leaching of chlorides from various types of Carboniferous coal mine spoils (Table 2) depends on concentration of chlorides in the coal mine spoils and flow rate of percolation of leaching waters (Fig. 3). The dynamics is very high in the case of the spoils characterized by intermediate to high salinity (samples II, III, and IV - Fig. 3). Treatment of 2 meters thick layer of the spoils with volume of water equal to the sum of precipitation for a half of year resulted in leaching of 62 to 76% of original amount of chlorides. The dynamics of leaching markedly decreases in the case of spoils characterized by low salinity (sample I - Fig. 3). The studies showed that the dynamics increases along with increase flow rate of leaching water from 1 to 4.75 dm3/m2 to decrease thereafter (Fig. 3B). The “in situ” studies on the dynamics of this process showed that 81-95°% of chlorides become leached out from spoils during the first year after disposal. This means that hazard of pollution of underground waters with ion Cl- in the vicinity of tip is practically limited to the first year. The migration of chlorides in waters beyond the tip may continue for some time, depending on geometry of the hydrodynamic field. The results of measurements of concentrations of chlorides in effluences from tips (Figs. 5, 6) and underground waters in the vicinity of tip (Fig. 7) showed that the currently used disposal sites create a continuous hazard of water pollution in their neighbourhood.